I have a 3D sword and I would like to limit the fire layer to just the blade. Is there anyway to do that within the effect settings or would it require some kind of masking and scenario.
You're basically going to need masking of some kind. The fire effect does generate fire based on pixel data of the fire's source layer.
While this might sound counterintuitive at first, what I would try is creating two point layers and having one follow the tip of the blade and the other following the base. Whether this is hand animation or tracked will depends on the shot. If the sword is being moved fast enough to create motion blur you have to do it by hand.
Once the points are animated create a black plane (for now put it above your sword and set opacity to about 30%) and add Lightsword. Parent the base and tip of the Lightsword to the points. Go into the Glow settings and turn Glow intensity to zero. Set core and glow colors to white. Adjust the width of the core to cover your blade and adjust persistence to match motion blur.
Set the Opacity of this layer to 100% and move it to the bottom of the layer stack. Create a Grade Layer and place it just above the Lightsword layer.
This creates a moving white line that follows the blade and it will be faster to animate the two points than a mask.. In fact, since you're sword is a 3D model you can parent the blade and tip points directly to the point used to animate the sword and you're ready to add Lightsword!
Now, when you add the Fire effect, choose the Grade Layer as the Source Layer for the Fire effect. Fire should spawn on the white pixels only.
One instance of the Fire effect is going to look cheesy. You're going to want to use at least two Fire effects with slightly different settings for more realism.
thanks for the info
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